In one of our PhD seminars, we are asked to re-read the classical paper by Garrett Hardin, The Tragedy of the Commons, published in Science in 1968. Here is my short summary.
The basic logic underlying the so called the tragedy of the commons is trivial. The marginal benefit from an individual's rational decision outweighs her marginal cost, but the society as a whole, was becoming worse-off due to overuse of the commons. So, totally different from Adam Smith's utopia of "invisible hand", the society in this situation has confronted a social dilemma, in which self-interests cannot result in social optimal outcome.
The author focused on the conundrum of overpopulation and its natural consequence of the overuse of resources and other kinds of social problems. How to solve this diemma? Can we realize Jeremy Benthem's goal of "the greatest good for the greatest number" at the same time through ingenious technique solutions? The answer was no and the reasons sprang from mathematical proof and biological facts.
Then what about property rights? Economists, like Ronald Coase had argued that property rights matter. Yes, they did matter. But according to the author, the power of property rights was limited because of pervasive existence of public goods problems and economic externalities. And furthermore, the efficacy of property right approach was also constrained by legal sanctions and enforcement of law.
Therefore, can we push this idea one more step so that we may simply rely exclusively on the legal system in our society? Indeed, we can control birth or overuse of the resources through legislation. But how can we legislate our temperence? By conscience? Can we rely on that? Again no. Conscience is self-eliminating and also can generate mental disorder and pathogenic effects.
At last, Dr. Hardin called upon some kind of social responsibility, say, mutual coercion to resolve this dilemma, "the only kind of coercion I recommend is mutual coercion, mutually agreed upon by the majority of the people affected." By common definition, this kind of mutual coercion can be regarded as social norms. It's simple, isn't it? However, further questions arised, where do social norms come from? Can norms stem from rationality assumptions? Can norms be designed? If so, through what way and what's the driving force?